Perfluoromethylenecyclopropane and polymers thereof

ABSTRACT

Thermal reaction of excess hexafluoroproylene epoxide with 2,3dichloro-1,1,3,3-tetrafluoropropene at 185*-210*C gives 1(chlorodifluoromethyl)-1-chloro-2,2,3,3-tetrafluorocyclopropane which can be dechlorinated by zinc in the presence of a saturated aliphatic ether diluent at 70*C to 140*C to give perfluoromethylenecyclopropane. Perfluoromethylenecyclopropane can be homopolymerized or copolymerized with vinyl comonomers to useful polymers using free radical initiators. Polymerization occurs by opening of the cyclopropane ring so that the copolymer contains pendant difluoromethylene groups which provide crosslinking sites.

. 5. ate-1 States atent 1 [111 3,872,066 Smart 1 1 Mar. 18, I975 [54]PERFLUOROMETHYLENECYCLOPRO- 3,308,107 3/1967 Selman et al. 260/875 APANE AND POLYMERS THEREOF 3,413,275 11/1968 Barkdoll et al. 260/375 A3,663,521 5/1972 Toy et al 260/87.5 A [75] Inventor: Bruce E. Smart,Wilmington, Del. [73] Assignee: E. I. du Pont de Nemours and p yWilmington DeL Primary Examiner Harry Wong, Jr.

[22] Filed: Jan. 18, 1974 [21] Appl. N0.: 434,416 [57] ABSTRACT RelatedApplication Data Thermal reaction of excess hexafluoroproylene epox- 1DWI-810R 0f 339,422, March 8, 1973, ide with2,3-dichloro-l,l,3,3-tetrafluoropropene at 31416553- 185210C givesl-(chlorodifluoromethyl)-l-chloro- 2,2,3,3-tetrafluorocyclopropane whichcan be dechlo- [52] us C! 260/8076, 117/124 117/155 rinated by zinc inthe presence ofa saturated aliphatic 117/161, 260/47 UA, 260/73, 260/785R, ether diluent at 70C to 140C to give perfluorome- 260/855 XA,260/863, 260/871, 260/875 thylenecyclopropane.Perfluoromethylenecyclopro- A, 260/875 B, 260/915, 260/648 ane can behomopolymerized or copolymerized with [511 f Cl Cost 5/00, Cosf 15/02Cogf 15/06 vinyl comonomers to useful polymers using free radi- [58]held of Search 260/921 cal initiators. Polymerization occurs by openingof the 260/877, 85.5, 80.76, 91.5 cyclopropane ring so that thecopolymer contains pendant difluoromethylene groups which provide cross-[56] References Cited linking sites UNITED STATES PATENTS 3,148,2239/1964 Jacobs et a1. 260/921 R 13 Claims, N0 DrawingsPERFLUOROMETHYLENECYCLOPROPANE AND POLYMERS THEREOF A preferred processfor making the perfluoromethylenecyclopropane of this inventioncomprises the twostep process shown in equations 1(a) and l(b):

Perfluoromethylenecyclopropane is believed to be highly toxic.

BACKGROUND OF THE INVENTION which the cyclopropane ring remains intactin the polymer. A homopolymer of tetrafluoroallene is known which haspendant difluoromethylene groups [Jacobs and Bauer, U.S. Pat. No.3,148,223 (1964)]. Copoly mers of tetrafluoroallene with vinyl monomers,specifically tetrafluoroethylene, are disclosed.

SUMMARY OF THE INVENTION The present invention comprises the novelcompound perfluoromethylenecyclopropane, the new compoundl-(chlorodifluoromethyl)-l-chloro-2,2,3,3 tetrafluorocyclopropane usedas an intermediate in the preparation thereof, and polymers thereofcontaining from 01% to 100% by weight of perfluoromethylenecyclopropaneand monomers which can be polymerized by free radical initiated chainpropagation.

DETAILED DESCRIPTION OF THE INVENTION The present invention is based onthe new monomer,

' pe rfluoromethylenecyclopropane.

The perfluoromethylenecyclopropane monomer undergoes ring-openingpolymerization so that the polymer units, both in the homopolymer andcopolymers with other monomers, contain pendant difluoromethyle'negroups, thus z II I C-CF CF- z n- F -C I The presence of the pendantdifluoromethylene groups in the polymer chains permits crosslinking in aconventional manner with little or no elimination of gaseousby-products.

The novel intermediatel-(chlorodifluoromethyl)-lchloro-2,2,3,3-tetrafluorocyclopropane isobtained by thermal reaction of hexafluoropropylene oxide with the known2,3-dichloro-l,l ,3,3-tetrafluoropropene within a temperature range ofl85-2l0C for a period of 8l2 hours. An excess of hexafluoropropyleneoxide, preferably 1.5-2.5 molar equivalents per mole of olefin, isusually employed in order to achieve satisfactory. conversion of theolefin. No added solvent is normally required for this reaction. Thecyclopropane reaction product (2) can be separated from (I) bydistillation, and unreacted (I) recycled in the reaction.

The novel intermediate (2) is subsequently converted by reaction l(b) tothe novel perfluoromethylenecyclopropane 3. A small amount of theisomeric product, l-trifluoromethyl-2-,3,3-trifluorocyclopropene, (4),is normally also formed in this reaction. The isomer (4) arises byisomerization of (3). Dechlorination is preferably effected with zincmetal or zinc/mercury amalgam. Various forms of zinc may be employed,i.e., zinc dust, granular zinc or zinc ribbon, although zinc dust ispreferred. It is also preferred, although not necessary, to activate thezinc dust before use. Activation is usually carried out by successivelywashing the zinc dust with dilute hydrochloric acid, acetone, ethanoland ether followed by drying under nitrogen. The molar ratio of zinc tointermediate (2) is not critical but should be at least 111 to achievecompleteconversion of (2). Excess zinc may be employed.

A solvent/diluent is normally required for the dehalogenation reaction,andsuitable solvents include selected aliphatic ethers, principallydi-n-alkyl ethers. Preferred solvents are dioxane and di-n-butyl etherwith dioxane being especially preferred. Although it is not necessary,the reaction is preferably carried out'at atmospheric pressure at orbelow the reflux temperature of the solvent. Adequate agitation isrequired since the zinc is not soluble in the reaction medium.

Although catalysts are not required, suitable catalysts may be employedin the dehalogenation reaction eg., a zinc halide such as zinc chlorideor zinc bromide. Such catalysts tend to increase the conversion rate of(2) to (3 but they also accelerate the isomerization of (3) to (4). If asuitably long contact time is employed, complete isomerization of (3) to4) is realized in the presence of zinc bromide. (see Example 10)Reaction temperature is important to reaction rate, but product may beobtained over a temperature range of l40C. However, it is preferred tocarry out the reaction in the temperature range l00C.

The reaction is normally conducted by addition of (2) to a well-stirredsuspension of zinc in a solvent/diluent, either with or without acatalyst. For maximum yields, very slow addition rates should be avoidedsince are these promote rearrangement of (3) to (4). The preferredprocedure is rapid addition of (3) once dehalogenation has commenced(30-60 minutes). The reaction mixture should be protected fromatmospheric moisture, and is preferably blanketed with an inertatmosphere, e.g., nitrogen.

The reaction product is usually separated by distillation, and itconsists ofa mixture of(3) and (4). The use of a rapid additionprocedure and the absence ofa catalyst leads to higher ratios of(3) to(4), frequently 9:1 to 20:1. Pure (3) can be obtained free of (4) byother separation techniques, for example, gas-liquid chromatography.However, it is not necessary to remove (4) to obtain satisfactorypolymerization of (3). If purified (4) is desired, it can be readilyobtained by catalytic isomerization of (3) (Example 10).

When copolymers are made, it is preferred to use from 0.1 to 90% byweight of the perfluoromethylenecyclopropane and most preferably from0.5 to 20% by weight.

The novel homopolymer andcopolymers of this invention can be prepared bystandard polymerization techniques, either neat or in the presence of anonreactive solvent for the monomers. Completely halogenated solventsare preferred with 1,1,2-trichloro-l,2,2- trifluoroethane (Freon 1 13)being especially preferred.

Both homopolymerization and copolymerization ofperfluoromethylenecyclopropane are initiated with free radicalinitiators which do not contain hydrogen atoms. Suitable initiatorsinclude perfluoropropionyl peroxide (3?), N F CF OOCF with 3P beingpreferred. The initiator concentration is not critical since onlycatalytic quantities are required, and concentrations of.0.0l% initiatorbased on total weight of monomers may be employed. It is preferred touse 0.1 to 1 weight of initiator..

Polymerizationtemperatures employed are dependent upon the particularinitiator used, since each initiator has a preferred temperature rangefor optimum formation of free radicals. With 3P initiator, it ispreferred to operate within the range of -50C with temperatures of 35Cbeing especially preferred.

The purity of the perfluoromethylenecyclopropane monomer is not criticalfor preparation of polymers,'

and the monomer may contain up to about 30% of the isomeric compound,1-trifluoromethy1-2,3,3-trifluorocyclopropene (4), and still be suitablefor polymerization. This isomer is inert to free radical polymerizationunder the conditions employed for successful polymerization ofperfluoromethylenecyclopropane and it is recovered unchanged.

Comonomers used to prepare copolymers withperfluoromethylenecyclopropane may be comprised of fluorine-containingcomonomers, or non-fluorinecontaining comonomers. Comonomers suitablefor use include those that undergo free radical-initiated polymerizationor copolymerization, preferably through a single unsubstituted group.Preferred fluorinecontaining comonomers include tetrafluoroethylene,hexafluoropropylene, vinyl fluoride, vinylidene fluoride,chlorotrifluoroethylene, perfluoro(2-methylene-4- methyl-1,3-dioxolane),and perfluoroalkylvinyl ethers, CF =CFOR;, where R, is perfluoroalkyl of1-3 carbon atoms. Preferred non-fluorine-containing comonomersacrylonitrile, 2-methylacrylonitrile, styrene, a-methylstyrene, vinylacetate, vinyl butyrate, methyl acrylate, methyl methacrylate, vinylchloride, vinyliacrolein.

Other comonomers include 2-alkylacrylonitriles, including the 2-ethyl,2-n-propyl, 2-neopentyl and 2- hexyl derivatives,2-trifluoromethylacrylonitrile, 2-carbomethoxy-acrylonitrile,2-carboethoxyand 2-carbobutoxyacrylonitrile, Z-phenylacrylonitrile, 2-fluoroacrylonitrile, trifluoroacrylonitrile, 2- acetoxyacrylonitrile,acrylic and methacrylic acids. alkyl esters of acrylic and methacrylicacid with up to 18 carbons in the alkyl group, including the ethyl,butyl, i-butyl, hexyl, n-dodecyl and octodecyl esters, maleic anhydride,o-, mand p-methylstyrene, ethyl vinyl ether and the alkyl vinyl ethers,halosubstituted styrenes, 2-vinylpyridine, N-vinylsuccinimide and otherN-vinylimides, vinyl esters of saturated fatty acids (C C range),including vinyl caproate, vinyl laurate, and vinyl palmitate, vinylbenzoate, and N- methylolacrylamide.

The novel polymers of this invention are useful since they are readilycrosslinked with little or no elimination of gaseous by-products byvirtue of the pendant difluoromethylene groups attached to the polymerchain. It is unnecessary to pro-treat the polymers prior tovulcanization to provide crosslinking sites, since these sites arepresent in the pendant difluoromethylene groups. Such crosslinkedpolymers exhibit outstanding heat and corrosion resistance.

In addition, the homopolymer and copolymers of this invention are usefulas oil and water repelling agents for glass and paper. For example,copolymers of perfluoromethylenecyclopropane with vinyl fluoride andwith vinylidene fluoride dissolved in acetone can be cast in thin filmson glass or paper substrates. Such substrates are rendered impervious towater by such treatment.

EMBODIMENTS OF. THE INVENTION The following examples illustrate specificembodiments of the invention.

EXAMPLE 1l-(Chlorodifluoromethyl)-1-ch1oro-2,2,3,3-tetrafluorocyclopropane Twoglass Carius tubes were each charged with 18.3 g (0.1 mole) of2,3-dichlorotetrafluoropropene'( 1 30 g (0.18 mole) ofhexafluoropropylene oxide (HFPO) and 0.5 g of phenothiazine and wereheated at 185C for 8 hours. The tube contents were transferred to adistillation pot and fractionated to afford 7.1 g of recovered (1); 8.8g of a mixture of 1- (chlorodifluoromethyl)- l-chloro-2,2,3,3-tetrafluorocyclopropane (2) and 20% (1), bp 4850C (analyzed by nmr);2.8 g of a mixture of (2) and 10% (1), bp 5155C; and 18.7 g ofpure (2),bp 57C; nmr (CCl ,CFC1 reference) (I) 54.0 (t oft, 2, J 21 Hz, J =2.5Hz), 140.8, 149.8 (AA'BB', m of m, 4, J 182 Hz, A: further split intotriplets (J 21 Hz) of multiplets, B: further split into triplets (J 2.5Hz) of multiplets). The fraction, bp 57C was analyzed.

3; F, Found: C. 20.30; Cl. 30.80; F,

I that EXAMPLE 2 Eight glass Carius tubes were each charged with 15 g ofa mixture of 1-(chlorodifluoromethyl)-1- chlorotetrafluorocyclopropane(27%) and 2,3- dichlorotetrafluoropropene (73%), bp 4356C, and 30 g ofHFPO and the tubes were heated at 185C for hours. The tubes were cooled,the contents combined and distilled to give 83.9 g of pure 1-(chlorodifluoromethyl)-1-chlorotetrafluorocyclopropane, bp 57-58C.

EXAMPLE 3 Perfluoromethylenecyclopropane A flask fitted with a droppingfunnel, water condenser, and a Dry Ice/acetone trap attached to thecondenser outlet was charged with 30 g of activated Zn dust, 3 g ofanhydrous ZnBr and 50 ml of anhydrous dioxane. This mixture was stirredand warmed to 80C in an atmosphere of nitrogen and then 23.3 g (0.1mole) of l-(chlorodifluoromethyl)-l-chlorotetrafluorocyclopropane in 20ml of anhydrous dioxane was added dropwise over a 3-hour period. Heatingat 80C was continued an additional 4 hours after the addition wascompleted. The collected trap material was distilled to afford 7.2 g(44%) of product, bp 46C, which was identified as a mixture of 85%perfluoromethylenecyclopropane, (3), ir (gas) 5.50 ,a (C=C); nmr (neat,CFCl ref) 57.3 (p,2,.l 6.6 Hz), 135.2 (t,4,J =6.6 Hz); and1-trifluoromethyl2,3,3-trifluorocyclopropene, (4), ir (gas) 5.29 ,aC=C); nmr (neat, CFCl ref) (b 60.3 (d of t,3,.l 7 Hz, 3 Hz), 100.0 (a'of q, 2, .l 36 Hz, 3 Hz), 116.7 (I ofq, 1, .1 =36 Hz, 7 Hz) The'Zn dustused in this example was activated by washing it with 10% hydrochloricacid followed by consecutive washings with water, ethanol, acetone andether. It was blown dry in a nitrogen atmosphere and finally dried at80C under reduced pressure for 30 minutes.

EXAMPLE 4 A slurry of 30g of Zn dust in 100 ml of anhydrous dioxane in a500 mlflask fitted with a water condenser, a -100C trap attached to thecondenser outlet, and a dropping funnel was warmed to 90C in a nitrogenatmosphere. A solution. of 23.3 g (0.1 mole) of 1-(chlorodifluoromethyl)-l-chlorotetrafluorocyclopropane in 25 ml of drydioxane was added dropwise to this well-stirred slurry until about halfof the solution was added. The addition was discontinued until after avigorous effervescent reaction had subsided (30 minutes). The remainderof (2) was added rapidly in one portion and a reaction temperature of90C was maintained for an additional 3 hours-The collected material inthe trap was fractionated to give 9.3 g (57%) of a mixture of 90% (3)and 10% (4), bp 6-7C.

EXAMPLE 5 The procedure of Example 3 was repeated except thel-(chlorodifluoromethyl l-chlorotetrafluorocyclopropane solution wasadded over a 5-hour period, and the reaction was continued at 80-'-85Cfor 60 hours after addition had been completed. A 30% yield of productwas obtained which consisted of 79% of (3) and 21% of (4).

EXAMPLE 6 The procedure of Example 4 was repeated. An yield of productwas obtained which consisted of 96% of (3) and 4% of (4).

EXAMPLE 7 was obbtained which consisted of 76.5% (3) and 23.5%

EXAMPLE 8 The general procedure of Example 4 was followed except thatZn/Hg amalgam was employed in place of Zn dust. After addition I of ca.half of the 1- (chlorodifluoromethyl 1 -chlorotetrafluorocyclopropanesolution, at C. (total time, 1.75 hrs), a small amount of product wascollected. The remainder of the1-(chlorodifluoromethyl)-l-chlorotetrafluorocyclopropane was addedrapidly and the reaction mixture was heated at 100C for 22 hours. A 37%yield of crude perfluoromethylenecyclopropane was obtained.

The Zn/Hg amalgam was prepared by washing g of 30 mesh granular Zn with500 ml of 5% aqueous hydrochloric acid containing lg of mercuricchloride until the surface was bright. The amalgam was filtered andwashed successively with 500 ml of distilled water, 500 ml anhydrousethanol, 500 ml of acetone, 500 ml of ether, and finally it was dried ina stream of nitrogen.

EXAMPLE9 l-(Trifluoromethyl)-2,3 3-trifluorocyclopropene A solution of23.3 g (0.1 mole) of l- (chlorodifluoromethyl)- l-chlorotetraf|uorocyclopropane in 20 ml of dry 1,2-dimethoxyethane wasadded dropwise (4 hrs.) to a well-stirred slurry of 30 g of Zn dust and4.0 g of ZnBr in 50' ml of dry 1,2- dimethoxyethane at 80C in anatmosphere of nitrogen. The volatile product was collected in a -l00Ctrap. The reaction mixture was stirred an additional 5 hours at 80Cafter the addition was completed. A total of 1.5 g (9% yield) of pure(4), bp 7C, was obtained.

EXAMPLE- 10 lsomerization of Perfluoromethylenecyclopropane to1-(Trifluoromethyl)-2,3,3-trifluorocyclopropene A sealed tube wascharged with 2.5 g of (3), 0.5 g of anhydrous ZnBr and 1 ml of dry bis(2methoxyethyl) ether and then heated at 100C for 7 hours. The votatileproduct (2.2g) was identified by nmr as pure (4).. Homopolymer ofPerfluoromethylenecyclopropane EXAMPLE 11 A sealed tube containing an85:15 mixture of perfluoromethylenecyclopropane and 1-(trifluoromethyl)-2,3.3-trifluorocyclopropene and a catalytic amount of perfluoropropionylperoxide (3P) in trichlorotrifluoroethane (Freon 1 l 3) solvent wasallowed to stand at 25 C for 60 hours. The tube was filled with a plugof the homopolymer of perfluoromethylenecyclopropane, mp 250-252C(vaporizes).

EXAMPLE 12 A 4-mm (id) X 20 cm tube was charged with l g of a 90:10mixture of(3) and (4) and 0.1 ml ofa solution of 3P intrichlorotrifluoroethane (0.1 g/ml) and the tube was allowed to stand at25C for 16 hours. The

EXAMPLE TABLE 1 Summary of Perfluoromethylenecyclopropane (PMCP)/TFECopolymerizations Thermal Gravimetric TFE PMCP Polymer Analysis (TGA) CExample g (mmoles) g (mmoles) (g) mp (C) 5% wt. loss 50% wt. loss 15A1.5 (15) 0.83 (5.1) 1.12" 267 470 542 158 2.5 0.83 (5.1) 1.79 288 494571 15C 5.0 0.83 (5.1) 2.05 297, 320" 500 579 15D 1.02 (10.2) 0.94 326"Thin opaque hriltlc films were pressed from this copolymer at ISO-215C.ir, 5.82 a (C=C) "Mixture nl'TFlZ homopolymer and copolymer.

TFE homupolymcrization.

tube was opened and a small amount of (4) was vol a tized (ir 5.29 ,u).The remaining solid polymer was dried in vacuo at 60C to afford ca. 0.8g of powdery white solid homopolymer of perfluoromethylenecyclopropane,ir (mull) 5.82 p. (C=C).

Anal. Calcd for (C,F,,)n: Found:

TGA: 5% wt. loss at 244C; 50% wt loss at 340C.

DTA: Tg: 78 to 75C region; melt endotherm onset at 249C, peaked at 272C;solidification exotherm (cooling) at 245C (peak, 231C); shallowendothermic degradation at 358C.

The homopolymer is insoluble in all common organic solvents, includingCHCl CH Cl diethyl ether, acetone, perfluorodimethylcyclobutane,hexafluoroisopropanol, benzene, ethanol, dimethylformamide,dimethylsulfoxide and acetonitrile. The homopolymer has a refractiveindex equivalent to tetrafluoro-l,3- dithietane.

EXAMPLE 13 Homopolymer of perfluoromethylenecyclopropane was preparedfrom a 74:26 mixture of (3) and (4) as described in Example 12.Optically clear, and brittle films were pressed at 200C.Copolymerization of Perfluoromethylenecyclopropane EXAMPLE 14 EXAMPLE 16B. With Acrylonitrile A small glass tube was charged with 0.27 g (5.1mmoles of acrylonitrile, 0.83 g (5.1 mmoles) ofperfluoromethylenecyclopropane and 0.1 ml of the 3P initiator solutionof Example 12, and the tube was heated to 40C. Polymerization occurredimmediately and ca. 0.3 g of cream colored, solid copolymer wasrecovered. The copolymer was soluble in dimethylformamide and thin'filmscould be pressed at 180C, ir 4.44, ,a (s, CN); 5.76 (w), 5.93 (w), 6.15(w) (C=C).

Anal. Found: C. 64.23; H, 5.28; N, 24.42; F, 4.53

DSC: Irreversible endo transition at 55C.

DTA: Exotherm onset at 300C, peaked at 330C.

Based on F, N, and H analyses, the copolymer contains approximately 40.5moles of acrylonitrile per mole of PMCP.

EXAMPLE 17 C. With Perfluoro( 2-methylene-4-methyl-l ,3- dioxolane)(PMD) A small glass tube was charged with 1.24 g (5.1 mmoles) of PMD,0.83 g (5.1 mmoles) of perfluoromethylenecyclopropane (90%) and 0.1 m1of 3P initiator solution, and the tube was warmed to 4045C. Poly mer wasformed immediately. A total of 1.0 g of white powdery solid copolymerwas obtained after removal of the unreacted monomers. The copolymer wassoluble in perfluorodimethylcyclobutane, and clear films were cast fromthis solvent, ir 5.69 (w), 5.82 (w) (C=C).

Anal C, 25.09;

DSC: No transition, to 50C. DTA: Endothermic crests at 126, 154, 212 andEXAMPLE 18 D. With Styrene ford ca. 0.35 g of tan solid copolymer,partial melting at 60-80C.

Anal: F, 11.90.

Analysis indicates approximately 7.6 moles of styrene per mole of PMCPin the copolymer.

EXAMPLE 19 E. With Vinyl Fluoride A thick-walled glass tube containing0.1 ml of 3P initiator solution, 0.81 g mmoles) ofperfluoromethylenecyclopropane (90%), and 0.55 g (12 mmoles) of vinylfluoride was allowed to stand 24 hours at room temperature. Aheterogeneous mixture with a viscous lower layer was formed. Thevolatiles were evaporated and the residual material was dried in vacuoat 50C for 48 hours to afford 0.726 g of brittle white solid copolymer.The copolymer was soluble in acetone and clear films cast from thissolvent displayed infrared absorption bands characteristic ofdifluoromethylene groups, 5.86 p (s, C=CF 5.77 p. (s, C=C).

Anal. Found: C, 36.24; H, 2.50; F, 59.38.

The analysis indicates approximately 2.2 moles of vinyl fluoride permole of PMCP in the copolymer.

EXAMPLE A glass tube containing 0.1 ml of 3P initiator solution, 0.81 g(5 mmoles) of perfluoromethylenecyclopropane (90%), and 0.28 g (6mmoles) of vinyl fluoride was heated at 50C for 20 hours. The volatileswere evaporated and the residual copolymer dried at 70C in vacuo for 16hours to leave 0.575 g of white solid copolymer, soluble in acetone, ir(cast film) 5.86 ,a (s, C=CF 5.76 a (s, C=C). Brittle, optically clearfilms were pressed at 100C (1000 psi), ir (film) 5.74, 5.79 p. (C=C).The copolymer decomposed at 100C.

Anal. Found: C, 36.86;

The analysis indicates approximately 1.84 moles of vinyl fluoride permole of PMCP in the copolymer.

EXAMPLE 21 EXAMPLE 22 A glass tube containing a mixture of 0.36 g (5.6

10 mmoles) of vinylidene fluoride, 0.81 g (5 mmoles) ofperfluoromethylenecyclopropane and 0.1 ml of 3P initiator solution washeated at 50C for 20 hours. The volatiles were evaporated and theresidue was dried at C for 16 hours to give 0.825 g of brittle solidcopolymer, soluble in acetone, ir (cast film) 5.80 a (s, C=CF Opticallyclear brittle films could be pressed at C (1000 psi), ir (film) 5.56 a(w), 5.67 ,u. (s), 5.81 p. (s). Some decomposition of the copolymeroccurred at 100C.

Anal. Found: C, 32.64; H, 1.49; F, 65.11

The analysis indicates approximately 2.3 moles of vinylidene fluorideper mole of PMCP in the copolymer.

EXAMPLE 23 G. With C hlorotrifluoroethylene A mixture of l 32 g (11.4mmoles) of Chlorotrifluoroethylene, 0.81 g (5 mmoles) ofperfluoromethylenecyclopropane (90%), and 0.1 ml of 3P initiatorsolution was allowed to stand 24 hours at 25C. The volatiles wereevaporated and the residue was dried at 50C for 48 hours in vacuo togive 033 g of powdery solid copolymer, ir (nujol mull) 5.84 t (s, C=CFAnal. Found: C, 21.14; F, 50.83; Cl, 28.46

The analysis indicates approximately 17.5 moles ofchlorotrifluoroethylene per mole of PMCP in the copolymer.

EXAMPLE 24 Terpolymerization of Perfluoromethylenecyclopropane A 400-mlreactor was charged with 5 g (0.031 mole) ofperfluoromethylenecyclopropane (90%), 45 g (0.7 mole) of vinylidenefluoride, 50 g (0.3 mole) of perfluoromethylvinyl ether, 2 ml of 3Pinitiator solution and 180 ml of trichlorotrifluoroethane, and thereactor was allowed to stand 4 hours at 25C.'The volatiles were removedat reduced pressure and the residue dried overnight at 70C in vacuo togive 7.5 g of white solid terpolymer, insoluble intrichlorotrifluoroethane, ir 5.82 p. (s, C=CF A mixture of 2 g of theterpolymer, 0.04 g of 0.1 g of MgO, and 0.04 g ofbenzyltriphenylphosphonium chloride was cured rapidly in a ShawburgCurometer at C.

EXAMPLE 25 A 400-ml reactor was charged with 5 g (0.031 mole) ofperfluoromethylenecyclopropane (90%), 14 g (0.14 mole) oftetrafluoroethylene, 44 g (0.264 mole) of perfluoromethylvinyl ether,2.5 ml of 3P initiator solution and m1 of trichlorotrifluoroethane, andthe reactor was heated at 30-35C for 4 hours. The volatiles were removedat reduced pressure and the residual solid dried to give 5.2 g of white,opaque, tough, terpolymer, ir 5.82 ,u. (s, C=CF 5.41 [.L (5).

Since obvious modifications and equivalents in the invention will beevident to those skilled in the arts, I propose to be bound solely bythe appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A polymer containing from 0.1'to by weightof units derived fromperfluoromethylenecyclopropane by ring-opening polymerization and fromto 99.9% complementally of units derived from at least one comonomerconsisting of a compound polymerizable by freeradical initiated chainpropagation.

2. The polymer of claim 1 containing 100% of units derived fromperfluoromethylenecyclopropane.

3. The polymer of claim 1 wherein said units derived fromperfluoromethylenecyclopropane are present in an amount of from 0.1 to90% by weight.

4. The polymer of claim 3 wherein said comonomer is at least one ofacrylonitrile, styrene, vinyl fluoride, vinylidene fluoride,tetrafluoroethylene, perfluoromethylvinylether, chlorotrifluoroethyleneor perfluoro(2-methylene-4-methyl-1,3-dioxolane).

5. The polymer of claim 4 wherein said comonomer is tetrafluoroethylene.

6. The polymer of claim 4 wherein said comonomer is vinyl fluorider 7.The polymer of claim 4 wherein the comonomer is chlorotrifluoroethylene.

8. The polymer of claim 4 wherein the comonomer is acrylonitrile.

9. The polymer of claim 4 wherein the comonomer is styrene.

10. The polymer of claim 4 wherein the comonomers areperfluoromethylvinyl ether and tetrafluoroethylene.

11. The polymer of claim 4 wherein the comonomers areperfluoromethylvinyl ether and vinylidene fluoride.

12. The polymer of claim 4 wherein said comonomer is vinylidenefluoride.

13. The polymer of claim 4 wherein said comonomer isperfluoro(2-methylene-4-methyl-l ,3-dioxolane

1. A POLYMER CONTAINING FROM 0.1 TO 100% BY WEIGHT OF UNITS DERIVED FROMPERFLUOROMETHYLENECYCLOPROPANE BY RINGOPENING POLYMERIZATION AND FROM 0TO 99.9% COMPLEMENTALLY OF UNITS DERIVED FROM AT LEAST ONE COMONOMERCONSISTING OF A COMPOUND POLYMERIZABLE BY FREERADICAL INITIATED CHAINPROPAGATION.
 2. The polymer of claim 1 containing 100% of units derivedfrom perfluoromethylenecyclopropane.
 3. The polymer of claim 1 whereinsaid units derived from perfluoromethylenecyclopropane are present in anamount of from 0.1 to 90% by weight.
 4. The polymer of claim 3 whereinsaid comonomer is at least one of acrylonitrile, styrene, vinylfluoride, vinylidene fluoride, tetrafluoroethylene,perfluoromethylvinylether, chlorotrifluoroethylene orperfluoro(2-methylene-4-methyl-1,3-dioxolane).
 5. The polymer of claim 4wherein said comonomer is tetrafluoroethylene.
 6. The polymer of claim 4wherein said comonomer is vinyl fluoride.
 7. The polymer of claim 4wherein the comonomer is chlorotri fluoroethylene.
 8. The polymer ofclaim 4 wherein the comonomer is acrylonitrile.
 9. The polymer of claim4 wherein the comonomer is styrene.
 10. The polymer of claim 4 whereinthe comonomers are perfluoromethylvinyl ether and tetrafluoroethylene.11. The polymer of claim 4 wherein the comonomers areperfluoromethylvinyl ether and vinylidene fluoride.
 12. The polymer ofclaim 4 wherein said comonomer is vinylidene fluoride.
 13. The polymerof claim 4 wherein said comonomer isperfluoro(2-methylene-4-methyl-1,3-dioxolane).